超级电容器用中孔炭复合电极材料研究进展

超级电容器是一类利用电化学双电层或电极材料在电极/溶液界面发生的氧化还原反应来存储能量的装置,除兼有常规电容器功率密度大和二次电池能量密度高的特点外,还具有可逆性好和循环寿命长等优点.本文重点介绍了近几年国内外对中孔炭材料、表面官能团修饰中孔炭材料、中孔炭-金属氧化物、中孔炭-导电聚合物等几类电极材料的研究现状;并且展望了超级电容器用中孔炭及其复合电极材料的当前研究热点和发展前景.     

Nanosized Fe3O4-modified activated carbon for supercapacitor electrodes

Nanosized Fe₃O₄-modified activated carbon composites for supercapacitor electrodes have been investigated. Structural and morphological characterizations of activated materials are carried out using X-ray diffraction and scanning electron microscopy, respectively. The electrochemical performances of the composite electrodes are evaluated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The experimental results show that the specific capacitances of the 10 wt % Fe₃O₄-modified activated carbon composite electrode (154.3 F g^?1) is highly improved compared with that of Fe₃O₄ (78.5 F g^?1) and AC (79.2 F g^?1) at the current density of 5 mA cm^?2, respectively. The charge/discharge tests show that it could retain 79.6% of its initial capacitance over 1000 cycles, suggesting its potential application for the fabrication of high-quality supercapacitors.     

Adsorptive removal of malachite green and Rhodamine B dyes on Fe3O4/activated carbon composite

This study demonstrates the adsorption experiments of toxic dyes malachite green (MG) and Rhodamine B (RB) on Fe₃O₄-loaded activated carbon (AC). AC, which is known to be a high-capacity adsorbent, was aimed to be easily separated from aqueous media by loading it with Fe₃O₄. Fe₃O₄-loaded AC was prepared by the coprecipitation method and named magnetic activated carbon (M-AC), and the produced M-AC was characterized by x-ray diffraction (XRD), thermogravimetric analysis (TGA), and pH_pzc analyses. MG and RB adsorption by the M-AC was performed separately by batch technique and the effects of adsorbent amount, solution pH, and initial dye concentration on the adsorption were explored. Maximum removal efficiencies were found to be 96.11% for MG and 98.54% for RB, and the Langmuir isotherm model was the most fitted isotherm model for the adsorption. The kinetic and thermodynamic studies showed that the adsorption proceeded via the pseudo-second-order kinetic model and endothermic in-nature for both dyes.     

Nitrogen-doped porous carbon coated on MnCo2O4 nanospheres as electrode materials for high-performance asymmetric supercapacitors

Spinel-based nanostructured materials are commonly used as promising electrode materials for supercapacitor applications. The combination of heteroatom-doped carbon material with spinel oxides substantially improves the specific capacitance and cyclic stability. In this work, dopamine-derived nitrogen-doped carbon was coated on spinel phase MnCo₂O₄ nanospheres using simple solvothermal and calcination methods. Surface morphology and the crystalline structure of the prepared MnCo₂O₄@Nitrogen-doped carbon were confirmed by FESEM and X-ray diffraction. The electrochemical performance of MnCo₂O₄@Nitrogen-doped carbon electrode material was analyzed by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. MnCo₂O₄@nitrogen-doped carbon exhibits the highest specific capacitance of 1200 F/g compared to MnCo₂O₄ spheres are 726 F/g at 1 A/g and exhibits excellent cyclic stability (capacitance retention of 87% at 7 A/g after 3000 cycles). The enhanced performance of the composite might be benefitted from the synergistic effect between nitrogen-doped carbon on porous MnCo₂O₄ spheres. Furthermore, an asymmetric supercapacitor device was fabricated by using the optimized composition of MnCo₂O₄@NC-2 as a positive electrode and nitrogen, sulfur-doped reduced graphene oxide (NS-rGO) as a negative electrode, respectively. This asymmetric supercapacitor device achieves a maximum energy density of 61.0 Wh/kg at a power density of 2889 W/kg and possesses excellent capacitance retention of 95% after 5000 cycles at 7 A/g.     

Synthesis and electrochemical properties of activated carbons and Li4Ti5O12 as electrode materials for supercapacitors

New activated nanoporous carbons, produced by carbonization of mixtures of coal tar pitch and furfural with subsequent steam activation, as well as electrochemically active oxide Li₄Ti₅O₁₂, prepared by thermal co-decomposition of oxalates, were tested and characterized as electrode materials for electrochemical supercapacitors. The phase composition, microstructure, surface morphology and porous structure of the materials were studied. Pure carbon electrodes as well as composite electrodes based on these materials obtained were fabricated. Two types of supercapacitor (SC) cells were assembled and subjected to charge–discharge cycling study at different current rates: (1) symmetric sandwich-type SC cells with identical activated carbon electrodes and different organic electrolytes, and (2) asymmetric hybrid SC cell composed by activated graphitized carbon as a negative electrode and activated carbon–Li₄Ti₅O₁₂ oxide composite as a positive electrode, and an organic electrolyte (LiPF₆–dimethyl carbonate/ethylene carbonate (DMC/EC). Four types of carbons with different specific surface area (1,000–1,600 m² g^?1) and texture parameters, as well as three types of organic electrolytes: Et₄NBF₄–propylene carbonate (PC), LiBF₄–PC and LiPF₆–DMC/EC in the symmetric SC cell, were tested and compared with each other. Capacitance value up to 70 F g^?1 for the symmetric SC, depending on the electrolyte microstructure and conductivity of the carbon material used, and capacitance of about 150 F g^?1 for the asymmetric SC cell, with good cycleability for both supercapacitor systems, were obtained.     

Pomegranate rind-derived activated carbon as electrode material for high-performance supercapacitors

In this paper, activated carbon materials were synthesized from pomegranate rind through carbonization and alkaline activation processes. The effects of pyrolytic temperature on the textual properties and electrochemical performance were investigated. The surface area of the activated carbon can reach at least 2200 m² g^?1 at different pyrolytic temperatures. It was found that, at the range of 600–900 °C, decreasing the carbonization temperature leads to the increase of t-plot micropore area, t-plot micropore volume, and capacitance. Further decreasing the carbonization temperature to 500 °C also leads to the increase of t-plot micropore area and t-plot micropore volume, but the capacitance is slightly poorer. The activated carbon carbonized at 600 °C and activated at 800 °C possesses very high specific area (2931 m² g^?1) and exhibits very high capacitance (～268 F g^?1 at 0.1 A g^?1 and ～242 F g^?1 at 1 A g^?1). There is no capacitance fading after 2000th cycle.     

Biomass-derived porous carbon electrode modified with nanostructured nickel-cobalt hydroxide for high-performance supercapacitors

Journal of Solid State Electrochemistry - Apple-derived porous carbon (denoted as APC) is successfully prepared and analyzed as a potential carbon material by hydrothermal carbonization and...     

Preparation of self-assembled porous flower-like nanostructured magnetite (Fe3O4) electrode material for supercapacitor application

Journal of Solid State Electrochemistry - Nanostructured electrode materials for supercapacitors have attracted research interest due to their high power density and long cycle life. Herein, porous...     

The preparation and performance of flocculent polyaniline/carbon nanotubes composite electrode material for supercapacitors

Polyaniline (PANI)/carbon nanotubes (CNTs) composite electrode material was prepared by in situ chemical polymerization. The structure and morphology of PANI/CNTs composite are characterized by Fourier infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. It has been found that a flocculent PANI was uniformly deposited on the surface of CNTs. The supercapacitive behaviors of the PANI/CNTs composite materials are investigated with cyclic voltammetry, galvanostatic charge/discharge, impedance, and cycle life measurements. The results show that the PANI/CNTs composite electrodes have higher specific capacitances than CNT electrodes and better stability than the conducting polymers. The capacitance of PANI/CNTs composite electrode is as high as 837.6 F g⁻¹ measured by cyclic voltammetry at 1 mV s⁻¹. Besides, the capacitance retention of coin supercapacitors remained 68.0% after 3,000 cycles.     

Photoluminescent Fe3O4/carbon nanocomposite with magnetic property

Fe(3)O(4)/carbon nanocomposite has been prepared by a facile chemical method, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy and scanning electron microscopy. The fluorescent and magnetic properties of the sample were investigated by fluorescence spectroscopy and vibrating-sample magnetometer, respectively. The results indicate that the Fe(3)O(4)/carbon nanocomposite exhibit good photoluminescent (emission ranging from 425 to 550 nm) and strong magnetic (saturation magnetization of 44.2 emu/g) properties.     

The environmental applications of activated carbon/zeolite composite materials

Over the past couple of years, the resurgence of placing an effective and sustainable amendment to combat against the auxiliary industrial entities, remains a highly contested agenda from a global point. With the renaissance of activated carbon, there has been a steadily growing interest in the research field. Recently, the adoption of zeolite composite, a prestigious advanced catalyst which formulates the enhancement of adsorption rate and hydrogen storage capability, has fore fronted to be a new growing branch in the scientific community. Confirming the assertion, this paper presents a state of art review of activated carbon/zeolite composite technology, its fundamental background studies, and environmental implications. Moreover, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbon/zeolite composite represents a potentially viable and powerful tool, leading to the plausible improvement of environmental preservation.     

一维氮掺杂碳包覆Fe3O4和Fe7S8纳米棒复合材料的制备及其储锂、储钠性能研究

以水热法制备的羟基氧化铁纳米棒作为反应原料,首先采用室温聚合法,在其表面包覆一层均匀的聚多巴胺,获得聚多巴胺包覆的羟基氧化铁,然后通过后续热处理,获得氮掺杂碳包覆的Fe3 O4和Fe7 S8复合材料(Fe3O4@NC和Fe7S8@NC).采用XRD、拉曼光谱仪、XPS、SEM以及TEM等技术对上述两种复合材料的结构和形...     

Electrochemical performance of NaCo2O4 as electrode for supercapacitors

Sub-micron-scaled sodium cobalt oxide （NaCo2O4） powders are prepared by a solid-state reaction method. Characterization using X-ray diffraction indicates that the synthesized NaCo2O4 has a hexagonal layered structure. The electrochemical performance of the NaCo2O4 electrodes is investigated using cyclic voltarnmetry and galvanostatic charge/discharge in NaOH solution. The results show that the specific capacitance of the NaCo2O4 electrode reaches 337 F/g over the potential range of 0.15-0.65 V at a mass normalized current of 50 mA/g. Moreover, NaCo2O4 exhibits very good stability and cycling performance as a supercapacitor material.     

Preparation and characterization of Fe_3O_4/Au composite particles

Colloid gold with different sizes has been widely used in immunoassay and nucleic acid detection mainly because of their properties for immobilization of biomolecules, such as antibodies and oligonucleo-tides, through chemical reactions via active group SH on the biomolecules. Magnetic particles modified with various chemical groups on their surface can not only exhibit good magnetic responsiveness to an external magnetic field but also immobilize biomolecules through these chemical groups. As…     

Fe_3O_4/Au composite nano-particles and their optical properties

The colloid gold and magnetic particle modified with various chemical groups have been widely used in the areas of biomedical and molecular biology[1―6]. Therefore, a great deal of attention has been given to the preparation and application of colloid go…     

Meso-macroporous Co3O4 electrode prepared by polystyrene spheres and carbowax templates for supercapacitors

Meso-macroporous Co₃O₄ electrode is synthesized by drop coating with a mixed solution containing Co(OH)₂ colloid, polystyrene spheres, and carbowax (namely polyethylene glycol), followed by calcining at 400?°C to remove polystyrene spheres and carbowax. For comparison, nonporous Co₃O₄ and mesoporous Co₃O₄ electrodes are prepared by drop coating with Co(OH)₂ colloid and with a mixed solution containing Co(OH)₂ colloid and carbowax under the same condition, respectively. Capacitive property of these electrodes is measured by cyclic voltammetry, potentiometry and electrochemical impedance spectroscopy. The results show that meso-macroporous Co₃O₄ electrode exhibits larger specific capacitance than those of nonporous Co₃O₄ electrode and mesoporous Co₃O₄ electrode at various current densities. The specific capacitance of meso-macroporous Co₃O₄ electrode at the current density of 0.2?A?g^?1 is 453?F?g^?1. Meanwhile, meso-macroporous Co₃O₄ electrode possesses the highest specific capacitance retention ratio at the current density ranging from 0.2 to 1.0?A?g^?1, indicating that meso-macroporous Co₃O₄ electrode suits to high-rate charge?Cdischarge.     

High rate capability of Fe/FeO/Fe3O4 composite as anode material for lithium-ion batteries

Fe/FeO/Fe₃O₄ composite was synthesized by a simple solid method using ferric citrate and phenolic resin as raw materials. The reaction processes of raw materials mixture were characterized by thermogravimetric analysis (TGA) under nitrogen. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the structure and morphology of the products. The results showed that the obtained material was octahedral Fe/FeO/Fe₃O₄ composite with a size of 2-4 μm. The electrochemical performances of Fe/FeO/Fe₃O₄ composite as anode material were also evaluated, which exhibited a stable specific capacity of 260.3 mAh g^-1 and an ideal initial coulombic efficiency of 90.8% in the range of 0.05~3 V at the 5C rate. A good rate capacity of Fe/FeO/Fe₃O₄ composite electrode was also shown by the charge-discharge testing even at the rate of 60C. The better rate capability of Fe/FeO/Fe₃O₄ electrode could be measured in higher temperature.     

An investigation on polycaprolactone/chitosan/Fe3O4 nanofibrous composite used for hyperthermia

Hyperthermia is considered as an effective supplementary cancer treatment. However, the uneven temperature distribution is the major challenge in hyperthermia. Nanotechnology could solve this problem by applying magnetic nanoparticles directly or in nanofibers as implants. Low solubility, poor cancer targeting, and leakage are limitations of free magnetic nanoparticles. In this work, Fe₃O₄ nanoparticles were loaded into polycaprolactone/chitosan blended nanofibers in various contents. Magnetic, chemical, physical, and morphology of the derived nanofibrous composites were then studied. The results showed the magnetic properties of the nanocomposite had low coercivity, which was close to superparamagnetic particles. Chemical analysis showed that components had no interaction with each other. Nevertheless, Fe₃O₄ was slightly transformed to other iron oxides. However, the magnetic analysis showed this transformation had no significant effect on final magnetic content of the nanofibers. The results of X‐ray diffraction (XRD) (19.5 nm), transmittance electron microscopy (TEM) (21.6 nm), and vibration sample magnetometer (VSM) (17 nm) suggested that the magnetic nanoparticles were single domain. Thermal analysis results showed that 7% Fe₃O₄ nanofibers had more heat increase as oppose to other nanofibrous composites in the alternative magnetic field (AMF). Nonetheless, the heat performance of 3% Fe₃O₄ nanofibers was more than others according to its specific power absorption (SPA). Therefore, due to the importance of using nanoparticles in the least possible content, this method can be used as a postsurgical treatment by applying these nanofibrous composites as implants on the tumor site. Moreover, these nanofiber composites could carry anticancer drugs, which are applied as a multi‐mode treatment system.     

Comparison of carbon aerogel and carbide-derived carbon as electrode materials for non-aqueous supercapacitors with high performance

Two porous carbon materials, one synthesised by pyrolysis of an organic aerogel prepared using sol–gel method and the other synthesised from molybdenum carbide by high temperature chlorination method, were tested as supercapacitor electrode materials in a non-aqueous tetraalkylammonium salt-based electrolyte. The gravimetric capacitance values calculated for the carbon aerogel (CAG)-based system were almost two times smaller (~55?F?g^?1) compared to carbide-derived carbon (C(Mo₂C))-based system (~125?F?g^?1). However, due to the very wide region of ideal polarizability, 3.6?V for C(Mo₂C) and 3.8?V for CAG-based test cells, very high energy densities up to 63?Wh?kg^?1 (34?Wh?dm^?3) and power densities up to 757?kW?kg^?1 (314?kW?dm^?3) were estimated for these systems, respectively. CAG-based system shows very short characteristic charge/discharge time constant values (0.05?s).